/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.spark.sql.connector.iceberg.read;

import java.util.Set;
import org.apache.spark.sql.connector.read.Scan;

/**
 * A mix-in interface for Scan. Data sources can implement this interface if they support dynamic
 * file filters.
 */
public interface SupportsFileFilter extends Scan {
  /**
   * Filters this scan to query only selected files.
   *
   * @param locations file locations
   */
  SupportsFileFilter.FileFilterMetric filterFiles(Set<String> locations);

  class FileFilterMetric {
    private int candidateFiles;
    private int matchingFiles;

    public FileFilterMetric(int candidateFiles, int matchingFiles) {
      this.candidateFiles = candidateFiles;
      this.matchingFiles = matchingFiles;
    }

    public int candidateFiles() {
      return candidateFiles;
    }

    public int matchingFiles() {
      return matchingFiles;
    }
  }
}
